The present invention relates to a method for finishing a surface of a work by electrolytic machining, and more particulary to a method for finishing the surface having a three-dimensional shape.
U.S. Pat. Nos. 3,527,686 and 3,607,689 disclose electrolytic machines. In the machine liquid electrolyte is continuously passed between an electrode and a work at a high speed during machining, so that residual products such as particles of eroded metal from the work, hydrogen gas, and others are discharged from the gap between the electrode and the work. However, in the case of the work having a complicated three-dimentional shaped recess, it is impossible to pass the liquid electrolyte through the gap having a complicated shape at a constant speed. The accuracy of the product is greatly influenced by the irregularities in the electrolyte flow. In addition, the concentration of the electrolyte at an outlet of an electrolyte tank is different from the concentration at an inlet, even if the pressure of the liquid is increased. Accordingly, it is impossible to produce accurate products.
In order to eliminate such disadvantages, the applicant proposed a system in which liquid electrolyte is not passed through an electrolyte tank and discharged together with residual products after application of pulses, and clean electrolyte is supplied to the tank for the subsequent process. However, pulses in the subsequent process are applied while the electrolyte moves in the gap between the work and the electrode. In such a state, flow rate of the electrolyte in the gap is different in localities, so that the electrolyte swirls in the gap. As a result, machining condition is different in localities, so that patterns dependent on the irregular flow of the electrolyte are formed on the surface of the work, which results in deterioration of surface quality of the work.